border-1px($color)
    position: relative
    &:after
        position: absolute
        left: 0
        bottom: 0
        width: 100%
        border-top: 1px solid $color
        content: ''
        transform-origin: bottom left
        transform: scaleY(0.5)

border-none()
    &:after
        display: none

bg-image($url)
    background-image: url($url + "@2x.png")
    @media(-webkit-min-device-pixel-ratio: 3), (min-device-pixel-ratio: 3)
        background-image: url($url + "@3x.png")